Conventional sensors usually have an inertia body, a lower shell in which the inertia body is received, and an upper shell which lies on the inertia body and into which it projects, the upper shell being part of a pivotally mounted sensor lever which swings on displacement of the inertia body and activates the locking mechanism.
Such a vehicle-sensitive sensor is known for example from the DE 298 22 610 and is installed into vehicle safety belt retractors. In the case of an impact of the vehicle, the inertia body, preferably a steel ball, moves and leads to the swinging of the sensor lever. A coupling catch on the sensor lever is thereby guided into the coupling teeth of a blocking mechanism, which finally blocks the belt spool and prevents a withdrawal of belt band. The triggering of the sensor also takes place, however, at a particular inclined position of the vehicle.